A needle free access valve is one where the valve can be opened using a needleless syringe. A needleless syringe is a syringe where the needle has been removed such that the front of the syringe has only the luer taper or luer lock. Such valves are known but suffer from a number of disadvantages.
A typical known valve has a body composed of two cylindrical containers. One container has a tubular opening into which the luer taper can be pressed. The other container has a tubular opening filled with a luer lock that allows the valve to be attached to various medical devices. Fluid flows through the luer taper upon depression of the syringe plunger and flows through the valve. The valve has a circular valve disk that can be forced open by the pressure of the fluid. When the fluid pressure stops, the valve returns to its closed position. This type of arrangement is entirely conventional. One disadvantage with this arrangement is that high levels of fluid flow can often not be obtained due to the design of the valve. That is, the valve itself is solid and fluid can flow only about the edge of the valve when the valve is opened. Another disadvantage is the lack of sterilisation around the inlet part of the valve.
A serious disadvantage with many existing one-way valves is that fluid can flow back into the valve from the body cavity or the body in which the needle etc has penetrated. This results in contamination, and a potential health hazard. Most valves are provided with some form of spring or bias to naturally bias the valve back into the closed position. Therefore, there would be a great advantage if it was possible to provide a one-way valve (for instance a needle free access valve) where there is little or no likelihood of backflow occurring upon removal or retraction of the syringe (or other device) to which the valve is attached.
Other disadvantages with conventional valves are the production costs, the relatively large number of components making up the valve, the difficulty in mass production of the valve.